Certain types of looms are capable of utilizing multiple filling yarns in a weaving process. The yarns are drawn from cones or packages mounted on a creel. These filling yarns are selected, one at a time, by a filling selector device and in a Dornier loom the selected filling yarn is drawn across the face of the cloth being woven by a rapier. Filling yarns, on occasion, do break and may not be fully pulled across the full width of the cloth by the rapier. In order to avoid missing or only partially inserted filling yarns in the finished cloth, a filling stop motion system, such as an Eltex stop motion, is positioned on the loom for detecting such fill yarn break failures and stops the operation of the rapier. Upon detection of a broken filling yarn, the stop motion system generates an electrical signal stopping the loom. The rapier is automatically returned to its starting point and will begin drawing yarn from the same selected yarn source as on the previous cycle during which the break occurred.
Although stop motion systems, such as the Eltex stop motion, employed throughout the industry operate quite effectively to detect a break in a filling yarn and stop the loom so that the broken yarn can be picked-up by the rapier again, the Eltex and other such systems fail to provide any data identifying which particular filling yarn broke. In order to determine which filling yarns are "problem yarns" or any reoccuring problems at the source of any such yarns, it is desirable to be able to keep track, over a period of time, of the frequency of breaks in particular yarns in order to identify faults so that corrective action may be taken.
Known loom data collection systems, such as disclosed in U.S. Pat. No. 3,728,680--Upshur, issued Apr. 17, 1973 and assigned to the assignee of this patent, do not provide the desired data.
The Upshur patent discloses a system for collecting data from looms, and particularly the reasons that looms have stopped. The Upshur system is concerned with the gathering of generalized information related to whether a loom was running or whether it stopped because of a break of a warp or filling yarn, and whether the break resulted from a mechanical failure or from a yarn running out. The system can be operated so that one or each loom or other device could be monitored with some predetermined frequency. Thus, use of the Upshur system provides information regarding filling stops, but one would know only that the machine stopped because of a broken filling yarn. Data indicating which particular filling yarn broke is not generated by the Upshur arrangement.
For looms operating in conjunction with an Eltex stop motion, or similar system, for stopping the loom when a filling yarn breaks it would be advantageous to compile data relating to the frequency of breakage of each filling yarn and to have this data stored in a permanent form for later use in identifying problem yarns or problems with particular positions in the yarn supply system.
In order to better understand the background of the present invention, a schematic of the electrical portions of the Eltex filling stop motion system is shown in FIG. 1. This system has a filling detector head including eight (8) eyelets. Each filling yarn is threaded so as to pass from its supply through one of the eyelets (one yarn associated with each eyelet) where it is held in a ready position so that when a yarn is engaged by the rapier, it will be drawn across through the fabric with the yarn being drawn through its eyelet. Associated with each of the eyelets are ceramic crystals X.sub.1 . . . X.sub.8, each being positioned so as to vibrate and generate an electrical signal when yarn is drawn through its associated eyelet. The signals generated by crystals X.sub.1 . . . X.sub.8 are amplified by transistor amplifiers 12, 14, 16. The amplified signals appear on output channels A and B of the filling detector head.
Output channels A and B from the filling detector head are coupled to a control box 18 (not shown in FIG. 1, but shown in FIGS. 2-3) and output signals thereon generate a loom stop signal for stopping the loom when a yarn breaks. A rapier switch box 20 (not shown in FIG. 1, but shown in FIGS. 2, 3 and 5) provides an "enable" signal to the control box indicating that the rapier is at a predetermined position in its transverse of the cloth being woven. Thus rapier switch box 20 creates a "sense window" restricting the time during which control box 18 makes a "decision" whether a filling yarn has broken by examining the channel A and B signals.
The combined action of the filling detector head and the control box produces loom stop output signals only when no filling yarn is being pulled through an eyelet by the rapier at the time defined by the sense window created by the enable signal from rapier switch box. However, it is not possible using such a conventional system to determine which particular filling yarn has broken.
Because stop motion systems, such as the Eltex stop motion, are so widely used throughout the industry, it is desirable to modify these existing units in order to provide the desired filling yarn data, rather than to add on to the loom yet another device for sensing the motion of each yarn. Therefore, there is a need for a relatively simple data generating arrangement providing the desired data that can be fabricated by modifying an existing stop motion system already in use on the loom. The present invention provides such a circuit.
For looms not having an Eltex stop motion or similar automatic loom shutdown device, the present invention can be implemented according to an alternate embodiment using discrete output filling sensors in place of a modified Eltex system.